A multi-pump displacement synchronous control hydraulic system

Abstract

A multi-pump displacement synchronous control hydraulic system, the multi-pump displacement synchronous control hydraulic system includes a power pump group, a piston rod, a swash plate, a throttle valve and a variable control valve; the power pump group includes a high-pressure piston pump and a variable oil cylinder. The inlet end of the high-pressure piston pump is communicated with the oil suction port S, the outlet end of the high-pressure piston pump is communicated with the rod chamber of the variable oil cylinder, the rod chamber of the variable oil cylinder is communicated with the inlet end of the throttle valve, the outlet end of the throttle valve is connected to the inlet end of the remote overflow valve, the rodless chamber of the variable oil cylinder is communicated with the outlet end of the variable control valve, and the outlet end of the high-pressure piston pump is respectively communicated with the inlet and outlet ends of the variable control valve. This design can make the pressure uniformly set by the remote overflow valve when multiple pumps operate simultaneously, and the displacement of the pumps is adaptively adjusted by the synchronous control valve composed of the throttle valve and the variable control valve, which can improve the service life of the pump group and the stability of the system.

Description

Technical Field

[0001] The present invention relates to an improvement of a multi-pump synchronous control system, belonging to the field of hydraulic systems, and particularly relates to a hydraulic system for synchronous control of multi-pump displacement. Background Art

[0002] The conveying hydraulic system of a chemical tanker is usually a central hydraulic loop closed system. The hydraulic power pump group transports hydraulic oil into the high-pressure main pipeline, and the oil in the main pipeline is connected to the hydraulic motor through the branch pipe. The characteristic of the conveying hydraulic system of a chemical tanker is that the hydraulic motor requires a large flow rate, and a certain number of motors need to be started and stopped at any time during operation. Therefore, it is usually necessary to start multiple power pump groups simultaneously to meet the system flow rate requirements. At the same time, each power pump group needs to be independently controlled and can be started and stopped at any time to ensure that it does not affect the operation of other pump groups. After starting a sufficient number of power pump groups, the oil output by the pump groups enters the hydraulic motor through the hydraulic main pipeline to drive a centrifugal pump inside the chemical tanker cabin, so as to transport the chemicals in the cabin to the port shore or other transport ship cabins.

[0003] However, when the number of started power pump groups is greater than or equal to two, these power pump groups need to work as synchronously as possible (the pressure and flow rate are basically the same) to extend the service life of the power pump groups and improve the reliability of the system. The characteristic of the conveying hydraulic system of a chemical tanker is that the number of actuators (motors) is large and the required flow rate is large. A single pump group usually cannot meet the use requirements. Therefore, it is necessary to operate one to a varying number (at least more than two) of power pump groups simultaneously. When two or more power pump groups operate simultaneously, since the power pump groups composed of motors and constant-pressure variable pumps operate independently, there will inevitably be a situation where the displacements of the hydraulic pumps in the two pump groups are different. In this way, the output powers of the two pump groups will be different. After long-term operation, the service life of one of the pump groups will inevitably be lower than that of the other pump group.

[0004] The Chinese invention patent with the application number CN2.11410088506.2 and the application date of March 12, 2.114 discloses a synchronous control hydraulic system for a plate shearing machine, which includes two shearing cylinders, two material stop cylinders, three blank holding cylinders and a shearing cylinder synchronous control system; the shearing cylinder synchronous control system includes an oil tank, two identical hydraulic pumps, a double-output shaft motor for driving the two hydraulic pumps to rotate, and two first one-way valves; the oil outlets of each first one-way valve are respectively connected with a first oil circuit, a second oil circuit and a third oil circuit. The first oil circuit includes a pilot-operated overflow valve and a two-position two-way solenoid valve; the second oil circuit includes a sequence valve and a two-position four-way solenoid valve; the third oil circuit includes a pressure reducing valve, a second one-way valve and a first accumulator; the double-output shaft motor drives two identical hydraulic pumps to supply oil to two identical shearing cylinders respectively, which can better ensure the synchronous accuracy of the two shearing cylinders; two shearing cylinders are respectively connected with a first accumulator to achieve pressure holding, but the problem of the working synchronization of the power pump group is not solved.

[0005] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of this patent application, and should not be regarded as an admission or any form of implication that this information constitutes the prior art already known to those of ordinary skill in the art. Summary of the Invention

[0006] The object of the present invention is to overcome the problem that the power pump group cannot be synchronously controlled in the prior art, and provides a multi-pump displacement synchronous control hydraulic system in which the power pump group can be synchronously controlled.

[0007] To achieve the above object, the technical solution of the present invention is: a multi-pump displacement synchronous control hydraulic system, which includes a power pump group, a piston rod, a swash plate, a throttle valve and a variable control valve;

[0008] The power pump group includes a high-pressure piston pump and a variable oil cylinder. The inlet end of the high-pressure piston pump is communicated with the suction port S, the outlet end of the high-pressure piston pump is communicated with the rod chamber of the variable oil cylinder, the rod chamber of the variable oil cylinder is communicated with the inlet end of the throttle valve, the outlet end of the throttle valve is connected with the inlet end of the remote overflow valve, the rodless chamber of the variable oil cylinder is communicated with the outlet end of the variable control valve, and the outlet end of the high-pressure piston pump is respectively communicated with the inlet and outlet ends of the variable control valve;

[0009] The structure of the first power pump group is the same as that of the second power pump group;

[0010] One end of the piston rod of the variable oil cylinder is connected with the swash plate of the high-pressure piston pump, and the other end of the piston rod of the variable oil cylinder is connected with one end of the throttle valve.

[0011] The power pump group also includes a unloading valve, and the outlet end of the throttle valve is communicated with the inlet end of the unloading valve.

[0012] The oil inlet end of the unloading valve communicates with the Mst oil port of a variable control valve.

[0013] Two one-way valves are arranged between the oil circuits of the unloading valve and the variable control valve, and the oil inlet ends of the two one-way valves communicate with the oil outlet end of the variable control valve.

[0014] The oil outlet end of the high-pressure piston pump communicates with the oil inlet end of a one-way valve.

[0015] The power pump set further includes a throttle orifice, a second throttle orifice and a third throttle orifice. The first throttle orifice and the second throttle orifice are arranged between the oil circuit of a variable oil cylinder and a variable control valve, and the third throttle orifice is arranged between the variable control valve and the R port of the control oil circuit.

[0016] The oil inlet end of the remote relief valve communicates with the XD oil ports of a power pump set and a second power pump set respectively.

[0017] A chute is formed on the front surface of the piston rod. The inner wall of the chute is in sliding force fit with the slider, and one end of the slider is connected to the swash plate.

[0018] A swash plate pin is inserted into the front surface of the swash plate.

[0019] The slider is in interference fit with the swash plate pin, and the swash plate pin is in clearance fit with the swash plate pin.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. In a multi-pump displacement synchronous control hydraulic system of the present invention, a power pump set includes a high-pressure piston pump and a variable oil cylinder. The oil inlet end of the high-pressure piston pump communicates with the suction port S. The oil outlet end of the high-pressure piston pump communicates with the rod chamber of the variable oil cylinder. The rod chamber of the variable oil cylinder communicates with the oil inlet end of a throttle valve. The oil outlet end of the throttle valve is connected to the oil inlet end of the remote relief valve. The rodless chamber of the variable oil cylinder communicates with the oil outlet end of a variable control valve. The oil outlet end of the high-pressure piston pump communicates with the oil inlet and outlet ends of the variable control valve respectively. The power pump set and the second power pump set have the same structure. When the hydraulic system composed of multiple power pump sets works, since the flow rate required by the actuator is large and multiple pumps need to operate simultaneously, when multiple pumps operate simultaneously, the pressure can be uniformly set by the remote relief valve, and the displacement of the pumps is adaptively adjusted by the synchronous control valve composed of the throttle valve and the variable control valve, which can improve the service life of the pump set and the stability of the system. Therefore, this design can perform synchronous control and adjustment with strong stability.

[0022] 2. In a multi-pump displacement synchronous control hydraulic system of the present invention, the pressure oil output by two pump sets enters the same main pipeline, so the pressures are equal; the control oil output by the two pump sets is controlled by the same remote overflow valve, so the pressures of the output control oil are also equal. In summary, the internal pressure losses of the two pump sets are equal. This internal pressure loss is mainly composed of the pressure losses generated by the throttle valve and the throttle nozzle at the variable control valve end. The spool of the throttle valve is mechanically connected to the variable mechanism. When the variable mechanism operates, the position of the spool of the throttle valve changes, and the pressure difference generated by the oil flowing through the throttle valve also changes. When the pump displacements of the two pump sets are inconsistent, the spool of the throttle valve of the pump with a larger displacement moves upward, the opening of the throttle valve becomes larger, and the generated pressure difference becomes smaller. This forces another factor, the pressure difference, to become larger to maintain balance. When the pressure difference becomes large enough to push the spring of the variable control valve, the variable control valve changes direction. At this time, the control oil output by the pump will enter the rod chamber of the variable cylinder, pushing the variable cylinder to move to the left, so that the displacement of the pump becomes smaller and finally stabilizes at the same displacement as the other pump. Therefore, this design has stable pressure and is safe to use.

[0023] 3. In a multi-pump displacement synchronous control hydraulic system of the present invention, one end of the piston rod of a variable cylinder is connected to the swash plate of a high-pressure piston pump, and the other end of the piston rod of the variable cylinder is connected to one end of a throttle valve. One side of the piston rod cylinder is a slope, and the spool of the throttle valve contacts the slope. When the piston rod moves to the left, it pushes the spool downward, the opening of the throttle valve decreases, and the pressure loss of the throttle valve increases; when the piston rod moves to the right, it pushes the spool upward, the opening of the throttle valve increases, and the pressure loss of the throttle valve decreases. Therefore, this design has a delicate piston rod structure and smoother adjustment. Brief Description of the Drawings

[0024] Figure 1 is a structural schematic diagram of the present invention.

[0025] Figure 2 is a structural schematic diagram of a variable cylinder in the present invention.

[0026] Figure 3 is a connection schematic diagram of a variable cylinder and a swash plate in the present invention.

[0027] Figure 4 is a working state schematic diagram of a variable cylinder in the present invention.

[0028] In the figure: a power pump set 1, a high-pressure plunger pump 1.1, a variable oil cylinder 2.1, a check valve 3.1, a remote relief valve 4, a throttle valve 5.1, two check valves 6.1, a variable control valve 7.1, a throttle nozzle 8.1, a unloading valve 9.1, two throttle nozzles 10.1, three throttle nozzles 11.1, a swash plate 101, a swash plate pin 102, a piston rod 2.11, a sliding groove 2.12, a sliding block 2.13, a second power pump set 2, a second high-pressure plunger pump 2.1, a second variable oil cylinder 2.2, three check valves 3.2, two throttle valves 5.2, four check valves 6.2, two variable control valves 7.2, four throttle nozzles 8.2, two unloading valves 9.2, five throttle nozzles 10.2, six throttle nozzles 11.2. Detailed implementation mode

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and the detailed implementation mode.

[0030] See Figures 1 to 4 , a multi-pump displacement synchronous control hydraulic system, the multi-pump displacement synchronous control hydraulic system includes a power pump set 1, a piston rod 2.11, a swash plate 101, a throttle valve 5.1 and a variable control valve 7.1;

[0031] The power pump set 1 includes a high-pressure plunger pump 1.1 and a variable oil cylinder 2.1. The inlet end of the high-pressure plunger pump 1.1 is communicated with the suction port S, the outlet end of the high-pressure plunger pump 1.1 is communicated with the rod chamber of the variable oil cylinder 2.1, the rod chamber of the variable oil cylinder 2.1 is communicated with the inlet end of the throttle valve 5.1, the outlet end of the throttle valve 5.1 is connected with the inlet end of the remote relief valve 4, the rodless chamber of the variable oil cylinder 2.1 is communicated with the outlet end of the variable control valve 7.1, and the outlet end of the high-pressure plunger pump 1.1 is respectively communicated with the inlet and outlet ends of the variable control valve 7.1;

[0032] The power pump set 1 and the second power pump set 2 have the same structure;

[0033] One end of the piston rod 2.11 of the variable oil cylinder 2.1 is connected with the swash plate 101 of the high-pressure plunger pump 1.1, and the other end of the piston rod 2.11 of the variable oil cylinder 2.1 is connected with one end of the throttle valve 5.1.

[0034] The power pump set 1 further includes a unloading valve 9.1, and the outlet end of the throttle valve 5.1 is communicated with the inlet end of the unloading valve 9.1.

[0035] The inlet end of the unloading valve 9.1 is communicated with the Mst oil port of the variable control valve 7.1.

[0036] A check valve 6.1 is provided between the oil circuits of a pressure relief valve 9.1 and a variable control valve 7.1, and the oil inlet ends of the two check valves 6.1 are communicated with the oil outlet end of a variable control valve 7.1.

[0037] The oil outlet end of a high-pressure piston pump 1.1 is communicated with the oil inlet end of a check valve 3.1.

[0038] The power pump group 1 further includes a throttle orifice 8.1, two throttle orifices 10.1 and three throttle orifices 11.1. The throttle orifice 8.1 and the two throttle orifices 10.1 are arranged between the oil circuits of a variable oil cylinder 2.1 and a variable control valve 7.1, and the three throttle orifices 11.1 are arranged between a variable control valve 7.1 and the R port of the control oil circuit.

[0039] The oil inlet end of the remote relief valve 4 is respectively communicated with the XD oil ports of a power pump group 1 and a second power pump group 2.

[0040] A chute 2.12 is formed on the front surface of the piston rod 2.11, and the inner wall of the chute 2.12 is in sliding force fit with the slider 2.13. One end of the slider 2.13 is connected to the swash plate 101.

[0041] A swash plate pin 102 is inserted into the front surface of the swash plate 101.

[0042] The slider 2.13 is in interference fit with the swash plate pin 102, and the swash plate pin 102 is in clearance fit with the swash plate pin 102.

[0043] The principle of the present invention is described as follows:

[0044] Part of the hydraulic oil output by a high-pressure piston pump 1.1 enters the hydraulic motor through a check valve 3.1 from port B through the main oil circuit, and another part of the control oil circuit enters the rod chamber of a variable oil cylinder 2.1 and the three throttle orifices 11.1, two check valves 6.1, and a throttle valve 5.1 respectively inside the high-pressure piston pump 1.1, and then flows into the remote relief valve 4 through the XD port of the throttle valve 5.1. Part of the oil passing through the throttle valve 5.1 is also communicated with a pressure relief valve 9.1 through the Mst port of a variable control valve 7.1, and the hydraulic oil in the rodless chamber of the variable oil cylinder 2.1 flows back to the fuel tank through the spring chamber of the variable control valve 7.1;

[0045] When a pressure relief valve 9.1 is in the right position, the pressure relief valve 9.1 is opened at this time, and the control oil output by a high-pressure piston pump 1.1 will all flow back to the fuel tank through the pressure relief valve 9.1. At this time, the output pressure of the high-pressure piston pump 1.1 is relatively small, which is the standby pressure. When the pressure relief valve 9.1 is in the left position, the pressure relief valve 9.1 is in the closed state. At this time, the control oil output by the high-pressure piston pump 1.1 can only flow into a throttle nozzle 11.1 through a check valve 6.1, and then finally flow into a remote pressure relief valve 4 through the XD port of a throttle valve 5.1. At this time, the output pressure of the high-pressure piston pump 1.1 is determined by the set value of the remote pressure relief valve 4. At this time, a pressure difference will be generated at both ends of the throttle nozzle 11.11 during the flow of the oil. When the pressure difference rises to a certain extent, the pressure oil on the left side of a variable control valve 7.1 will overcome the sum of the spring force and the hydraulic pressure in the spring chamber on the right side of the variable control valve 7.1, pushing the variable control valve 7.1 to change direction to the right, so that the pressure oil output by the high-pressure piston pump 1.1 enters the rodless chamber of a variable cylinder 2.1, pushing the variable piston to move left, and the displacement of the high-pressure piston pump 1.1 becomes smaller.

[0046] Embodiment 1:

[0047] A multi-pump displacement synchronous control hydraulic system, the multi-pump displacement synchronous control hydraulic system includes a power pump group 1, a piston rod 2.11, a swash plate 101, a throttle valve 5.1 and a variable control valve 7.1; the power pump group 1 includes a high-pressure piston pump 1.1 and a variable cylinder 2.1. The inlet end of the high-pressure piston pump 1.1 is communicated with the suction port S, the outlet end of the high-pressure piston pump 1.1 is communicated with the rod chamber of the variable cylinder 2.1, the rod chamber of the variable cylinder 2.1 is communicated with the inlet end of the throttle valve 5.1, the outlet end of the throttle valve 5.1 is connected with the inlet end of the remote pressure relief valve 4, the rodless chamber of the variable cylinder 2.1 is communicated with the outlet end of the variable control valve 7.1, and the outlet end of the high-pressure piston pump 1.1 is respectively communicated with the inlet and outlet ends of the variable control valve 7.1; the internal spool of the throttle valve 5.1 is a spool structure, and the spool is in direct contact with the high-pressure piston pump 1.1 and the variable cylinder 2.1. The position where the top of the variable cylinder 2.1 contacts the spool is a 5° inclined plane, and the vertical position of the spool will change following the horizontal sliding of the variable cylinder 2.1 of the high-pressure piston pump 1.1, and the valve opening of the throttle valve 5.1 changes accordingly. Thus, the hydraulic pressure difference across the throttle valve 5.1 changes. The inlet of the throttle valve 5.1 is connected to the Mst port of the variable control valve 7.1, and a check valve 6.1 is installed therebetween to prevent the oil from flowing back from the XD port of the power pump group 1; the power pump group 1 and the second power pump group 2 have the same structure.

[0048] When the present invention is applied:

[0049] A high-pressure plunger pump 1.1 and two high-pressure plunger pumps 2.1 suck oil from the fuel tank. The output main oil circuits respectively enter the same main pipeline through a one-way valve 3.1 and a two-way one-way valve 3.2. Another part of the control oil respectively passes through a three-way throttle 11.1, a six-way throttle 11.2 and a one-way throttle valve 5.1, a two-way throttle valve 5.2 and converges into the same remote overflow valve 4 from the XD port. Since the two plunger pumps share the same pressure oil port and the same overflow valve 4, the sum of the pressure differences inside the two plunger pumps passing through the three-way throttle 11.1, the six-way throttle 11.2 and the one-way throttle valve 5.1, the two-way throttle valve 5.2 is equal;

[0050] When the displacement of the two plunger pumps is inconsistent, when the swash plate swing angle of the high-pressure plunger pump 1.1 is greater than that of the two high-pressure plunger pumps 2.1, the spool of the one-way throttle valve 5.1 corresponding to the high-pressure plunger pump 1.1 moves upward, and the valve port of the one-way throttle valve 5.1 increases. At this time, the pressure difference of the one-way throttle valve 5.1 becomes smaller. Since the sum of the pressure differences of the one-way throttle valve 5.1 and the three-way throttle 11.1 is equal, the pressure difference at both ends of the three-way throttle 11.1 will become larger. When this pressure difference increases enough to overcome the spring force of the variable control of a variable control valve 7.1, the spool of the variable control valve 7.1 will move to the right under the action of the hydraulic pressure. At this time, the pilot hydraulic oil output by the high-pressure plunger pump 1.1 will flow into the rodless cavity of a variable oil cylinder 2.1 through the variable control valve 7.1. Since the effective area of the rodless cavity of the variable oil cylinder 2.1 is larger than that of the rod cavity at this time, under the push of the hydraulic pressure, the variable piston inside the high-pressure plunger pump 1.1 will move to the left, forcing the displacement of the high-pressure plunger pump 1.1 to become smaller. When the variable piston of the high-pressure plunger pump 1.1 moves to the left for a certain distance, the spool of the one-way throttle valve 5.1 corresponding to the high-pressure plunger pump 1.1 will move downward, and the valve port of the one-way throttle valve 5.1 becomes smaller. Therefore, the pressure difference of the one-way throttle valve 5.1 becomes larger, and finally stabilizes at the same swash plate swing angle and basically the same displacement of the two plunger pumps.

[0051] Embodiment 2:

[0052] Embodiment 2 is basically the same as Embodiment 1, and the difference is that:

[0053] A multi-pump displacement synchronous control hydraulic system, one end of the piston rod 2.11 of the variable oil cylinder 2.1 is connected to the swash plate 101 of the high-pressure plunger pump 1.1, and the other end of the piston rod 2.11 of the variable oil cylinder 2.1 is connected to one end of the one-way throttle valve 5.1.

[0054] Embodiment 3:

[0055] Embodiment 3 is basically the same as Embodiment 2, and the difference is that:

[0056] A multi-pump displacement synchronous control hydraulic system. The power pump group 1 further includes a unloading valve 9.1. The oil outlet end of a throttle valve 5.1 is communicated with the oil inlet end of a unloading valve 9.1, which can quickly unload the power pump group 1 and reduce the standby pressure of the power pump group 1. The oil inlet end of the unloading valve 9.1 is communicated with the Mst oil port of a variable control valve 7.1. Two one-way valves 6.1 are arranged between the oil circuits of the unloading valve 9.1 and the variable control valve 7.1, and the oil inlet ends of the two one-way valves 6.1 are communicated with the oil outlet end of the variable control valve 7.1. The oil outlet end of a high-pressure plunger pump 1.1 is communicated with the oil inlet end of a one-way valve 3.1. The power pump group 1 further includes a throttle orifice 8.1 and two throttle orifices 10.1, which are arranged between the oil circuits of a variable oil cylinder 2.1 and a variable control valve 7.1. The oil inlet end of the remote overflow valve 4 is respectively communicated with the XD oil ports of the power pump group 1 and the second power pump group 2. By adjusting the pressure setting value of the remote overflow valve 4, the XD oil port pressures of the power pump groups 1 and 2 can be controlled, and thus the output pressures of the power pump groups 1 and 2 can be controlled. The outlet of the remote overflow valve 4 is connected to the oil tank, and the excess oil overflows back to the oil tank. The control oil output by the high-pressure plunger pump 1.1 enters the left and right sides of the variable control valve 7.1 respectively. The spring in the right spring chamber has a certain pre-compression amount, providing a spring force to the left for the valve core. During the working process, the hydraulic oil pressure on the left side of the variable control valve 7.1 is compared with the sum of the hydraulic oil pressure on the right side and the spring force. When the hydraulic pressure on the left side is greater than the sum of the hydraulic pressure on the right side and the spring force, the hydraulic oil will push the valve core of the variable control valve 7.1 to move rightward. The hydraulic oil output by the high-pressure plunger pump 1.1 enters the rodless cavity of the variable oil cylinder 2.1 through the variable control valve 7.1, pushing the variable piston to move leftward, and the displacement of the high-pressure plunger pump 1.1 becomes smaller.

[0057] Embodiment 4:

[0058] Embodiment 4 is basically the same as Embodiment 3, and the difference lies in:

[0059] A multi-pump displacement synchronous control hydraulic system, wherein a chute 2.12 is provided on the front surface of the piston rod 2.11, and the inner wall of the chute 2.12 is in sliding force fit with the slider 2.13, and one end of the slider 2.13 is connected to the swash plate 101; a swash plate pin 102 is inserted into the front surface of the swash plate 101; the slider 2.13 is in interference fit with the swash plate pin 102, and the swash plate pin 102 is in clearance fit with the swash plate pin 102. One surface of the cylinder of the piston rod 2.11 is an inclined surface, and the valve core of a throttle valve 5.1 contacts the inclined surface. When the piston rod 2.11 moves to the left, it pushes the valve core downward, the valve opening of the throttle valve 5.1 decreases, and the pressure loss of the throttle valve 5.1 increases; when the piston rod 2.11 moves to the right, it pushes the valve core upward, the valve opening of the throttle valve 5.1 increases, and the pressure loss of the throttle valve 5.1 decreases; in addition, there is a flat groove on the opposite surface of the inclined surface of the cylinder of the piston rod 2.11. The slider 2.13 moves back and forth in the chute 2.12 with a gap. The slider 2.13 is in interference connection with the swash plate pin 102, and the swash plate pin 102 is in clearance fit with the swash plate 101. When the piston rod 2.11 moves to the left, it will drive the slider 2.13 to slide forward, and the swash plate 101 will swing counterclockwise around the swash plate pin 102, and the displacement of a high-pressure piston pump 1.1 becomes smaller; when the piston rod 2.11 moves to the right, it will drive the slider 2.13 to move backward, and the swash plate 101 will swing clockwise around the swash plate pin 102, and the displacement of a high-pressure piston pump 1.1 becomes larger.

[0060] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modification or change made by those of ordinary skill in the art according to the content disclosed in the present invention shall be included in the protection scope recorded in the claims.

Claims

1. A hydraulic system for synchronous control of multi-pump displacement, characterized in that : The multi-pump displacement synchronous control hydraulic system includes a power pump unit (1), a piston rod (2.11), a swash plate (101), a throttle valve (5.1) and a variable control valve (7.1); The power pump unit (1) includes a high-pressure piston pump (1.1), a variable oil cylinder (2.1). The inlet end of the high-pressure piston pump (1.1) is communicated with the suction port S. The outlet end of the high-pressure piston pump (1.1) is communicated with the rod chamber of a variable oil cylinder (2.1). The rod chamber of the variable oil cylinder (2.1) is communicated with the inlet end of a throttle valve (5.1). The outlet end of the throttle valve (5.1) is connected to the inlet end of a remote relief valve (4). The rodless chamber of the variable oil cylinder (2.1) is communicated with the outlet end of a variable control valve (7.1). The outlet end of the high-pressure piston pump (1.1) is respectively communicated with the inlet and outlet ends of a variable control valve (7.1); The structures of the power pump unit (1) and the second power pump unit (2) are the same; One end of the piston rod (2.11) of the variable oil cylinder (2.1) is connected to the swash plate (101) of a high-pressure piston pump (1.1), and the other end of the piston rod (2.11) of the variable oil cylinder (2.1) is connected to one end of a throttle valve (5.1).

2. The hydraulic system for synchronous control of multi-pump displacement according to claim 1, characterized in that: The power pump unit (1) further includes a unloading valve (9.1). The outlet end of the throttle valve (5.1) is communicated with the inlet end of the unloading valve (9.1).

3. The hydraulic system for synchronous control of multi-pump displacement according to claim 2, characterized in that: The inlet end of the unloading valve (9.1) is communicated with the Mst oil port of a variable control valve (7.1).

4. The hydraulic system for synchronous control of multi-pump displacement according to claim 3, characterized in that: Two one-way valves (6.1) are arranged between the oil circuits of the unloading valve (9.1) and the variable control valve (7.1). The inlet ends of the two one-way valves (6.1) are communicated with the outlet end of the variable control valve (7.1).

5. The hydraulic system for synchronous control of multi-pump displacement according to claim 1, characterized in that: The outlet end of the high-pressure piston pump (1.1) is communicated with the inlet end of a one-way valve (3.1).

6. The hydraulic system for synchronous control of multi-pump displacement according to claim 1, characterized in that: The power pump unit (1) further includes a throttle orifice (8.1), two throttle orifices (10.1) and three throttle orifices (11.1). The throttle orifice (8.1) and the two throttle orifices (10.1) are arranged between the oil circuits of the variable oil cylinder (2.1) and the variable control valve (7.1). The three throttle orifices (11.1) are arranged between the variable control valve (7.1) and the control oil circuit R port.

7. The hydraulic system for synchronous control of multi-pump displacement according to claim 1, characterized in that: The inlet end of the remote relief valve (4) is respectively communicated with the XD oil ports of the power pump unit (1) and the second power pump unit (2).

8. The hydraulic system for synchronous control of multi-pump displacement according to claim 1, characterized in that: A chute (2.12) is formed on the front surface of the piston rod (2.11). The inner wall of the chute (2.12) is in sliding force fit with a slider (2.13). One end of the slider (2.13) is connected to the swash plate (101).

9. The hydraulic system for synchronous control of multi-pump displacement according to claim 8, characterized in that: A swash plate pin (102) is inserted into the front surface of the swash plate (101).

10. The hydraulic system for synchronous control of multi-pump displacement according to claim 9, characterized in that: The slider (2.13) is in interference fit with the swash plate pin (102), and the swash plate pin (102) is in clearance fit with the swash plate pin (102).

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